Protective effect of astaxanthin against La2O3 nanoparticles induced neurotoxicity by activating PI3K/AKT/Nrf-2 signaling in mice.

Lanthanum oxide nanoparticles (La2O3 NPs) are used in photoelectric and catalytic applications. Astaxanthin (ASX) is a red carotenoid pigment with antioxidant and anti-inflammatory properties, and the antioxidant activities promote neuroprotection. This study explored the effect of ASX supplementation on La2O3 NP-induced neurotoxicity in mice and the molecular mechanisms of such protective effects. Amongst our findings, we determined that ASX treatment significantly attenuated La2O3 NP-induced behavioural abnormalities, histopathological evidence of hippocampal injury and ultrastructural changes in the CA1 region of the hippocampus. ASX treatment also markedly inhibited the production of ROS and activated PI3K/AKT signaling, which facilitated the nuclear translocation of Nrf-2 and reversed the down-regulation of HO-1, NQO1 and GCLM proteins in the hippocampus that were induced by sub-chronic exposure to La2O3 NPs. Administration of ASX to mice receiving La2O3 NPs also resulted in decreased expression of iNOS, IL-1β, TNF-α, COX-2, Bax and Caspase-3 and in increased expression of BDNF, NGF and Bcl-2 observed in response to La2O3 NPs. In conclusion, ASX had a markedly protective effect against the negative sequelae associated with La2O3 NP-induced neurotoxicity. This may result from the activation of the PI3K/AKT/Nrf-2 signaling and via the inhibition of oxidative stress, neuroinflammation and cellular apoptosis.